MC-306 and DOT 406 tankers are elliptical when viewed from the rear. By far the most common product carried in them is gasoline or other flammable liquids. They usually have a heavy, built-up top that is hollowed out to contain small spills. These tankers have one or more domes and dome covers, generally one dome per compartment in the tank.

MC-307 (DOT-407)

Low-pressure bulk liquid cargo tank

Pressure—up to 40 psi @ 70ºF

Horse shaped” shaped cross section

Flat or slightly rounded ends

Stainless steel is primary material of construction

May be insulated. Insulation may hide tank shape—may not appear to be horseshoe shaped

Manway usually center (top) of tank

Discharge valves usually center (bottom) of tank

If multi-compartmented, will have a separate manhole for each compartment

Emergency shutoff –drivers side front

Rollover protection to prevent manholes from opening up on rollover, normally

center of tank top

Average maximum capacity–6,000 gallons

Contents:
NORMALLY—mild acids, however, may be water, milk, or combustible liquids

MC-307/DOT 407 tankers are a usually a horseshoe shape when viewed from the rear. They carry vegetable oils, syrups, and milk – and they also carry solvents, lubricants, mild corrosives, etc. The horseshoe shape tanks are insulated – the shape you see is the thin aluminum insulation shell cover. Some of these tankers are uninsulated, appear round with small ridges, and are usually unpainted aluminum if un-insulated. The domes in these tankers are usually in the center of the long axis of the tank, but can be multiples or in other locations.